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Medically reviewed by
Dr Daniel Atkinson
GP Clinical Lead
on August 02, 2022.
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What Caverject dosages are available

Caverject comes in three different dosages. For the vials these include 10mcg, 20mcg and 40mcg, but the prescribing clinician can alter the dosage if needed. Caverject Impulse Dual Chamber dosages only come in 10mcg and 20mcg, but you can administer it as more or less – in increments of 25%. So the starting dose with the dual chamber is often 2.5mcg, which is gradually increased until the ideal dose is reached.

Finding the right dosage of Caverject can take time, though. The standard dosage tends to be between 5mcg (using half of the 10mcg dual chamber) and 20mcg, which is usually effective for the men using it.

Your doctor will slowly increase the dosage to find the right one for you, minimising risks and maximising effectiveness, a process called titration. If you find the medication doesn’t provide you with the results you need without unwanted side effects, a different erectile dysfunction treatment might be suggested.

Are Viridal dosages the same as Caverject?

Viridal Duo is essentially the same product as Caverject in regards to its active ingredient and dosages. Whilst both products are injected, the injection devices aren’t the same, so the instructions will differ slightly.

If you’re swapping between Caverject and Viridal, be sure to tell your prescribing clinician so they can make sure you’re comfortable with the new instructions.

Caverject Dual Chamber, Vials & Viridal Duo 10mcg

The lowest dosage product available for alprostadil injections is 10mcg. Caverject Dual Chamber and Caverject 10mcg are essentially the same product but the Dual Chamber device is unique to Caverject whereas the vials are administered through a needle. You can set the dosage on the device or, when using the vials, it can be measured on the syringe.

The Viridal 10 starter pack uses the EasyDuo device, its instructions differ slightly from the Caverject Dual Chamber.

At the start of your treatment, it’s likely that your doctor will recommend a dosage of 2.5mcg to 5mcg, whichever the product. The 10mcg dosage is the lowest of the standard products but it’s usually effective enough for most that use it.

If you don’t achieve the results you want from this dosage, and you haven’t experienced any unpleasant side effects, your prescribing clinician might suggest increasing the dosage.

Caverject Dual Chamber, Vials & Viridal Duo 20mcg

The Caverject 20mcg injection is at the higher end of the standard dosages. As you might expect, it’s more reliable but also presents a higher risk of side effects, as will all alprostadil 20mcg products.

This also goes for the Viridal Duo 20mcg continuation pack, although it’s likely you’ll only be prescribed this if it’s been proven you can tolerate the dosage. If this dosage is still found to be lacking, it can still be increased to 40mcg.

Caverject Vials & Viridal Duo 40mcg

The 40mcg dose is the highest dosage of Caverject and Viridal Duo. It can be found in the products Viridal Duo Continuation 40mcg and Caverject 40mcg vials. There is no Caverject Dual Chamber 40mcg dosage.

It’s unlikely your doctor will prescribe this dosage as a starting point, unless you have previous experience with the medication and it was found that the dosage didn’t cause you any side effects. More often than not, you’ll build up to Caverject 40mcg and Viridal 40 mcg dosages after the lower strength products have been found to be ineffective.

Active ingredient
Made/marketed by
Available doses
Works in
Lasts for
Individual Vitaros sachet

Vitaros Cream


Cream that you apply to the tip of the penis and works from 5 minutes.

See treatment  
5-30 minutes
1-2 hours
Vial of Caverject



Injectable treatment that works from 5 minutes. Good option if tablets haven't worked for you.

See treatment  
10mcg/ml 20mcg/ml 40mcg/ml
10-15 minutes
1 hour
Treated branded box



Small pellet you insert into the tip of the penis, that works from 10 minutes.

See treatment  
500mcg 1000mcg
5-10 minutes
30-60 minutes
Two Viridal Duo Plungers

Viridal Duo


Injectable treatment that's very similar to Caverject. Works from 5 minutes and lasts up to 1 hour.

See treatment  
10mg 20mg 40mg
5-15 minutes
1 hour
  • Manufacturers subject to change.
  • Start and duration of effects are estimations.
  • For more detailed information on your medication, read the patient information leaflet.

What Vitaros Cream dosages are there?

Vitaros cream doses include 200mcg and 300mcg, both available in a 3g tube. Vitaros is generally well tolerated by those that use it but there are occasions where a lower dosage will be recommended.

If you haven’t used Vitaros cream before, starting at the lower dosage is usually recommended before increasing it if needed.

Vitaros 3mg/g cream

Vitaros 3mg/g cream, sometimes called Vitaros 300mcg cream, is the highest dosage of Vitaros. You might be prescribed this dosage at the start of treatment but if you experience any side effects it can be decreased to 200mcg per 100g of cream (2mg/g).

Vitaros 2mg/g cream

The lower dose of Vitaros is 200mcg and it’s prescribed either at the start of treatment, if your prescribing clinician thinks there’s a risk of side effects, or if you experience side effects from the higher dosage of 300mcg but the treatment was effective.

If you still experience problems with the 2mg/g dose or it proves to be ineffective, your prescribing clinician might suggest another treatment.

What MUSE dosages are available?

There are four doses of MUSE: 125mcg, 250mcg, 500mcg and 1000mcg. This range allows your prescribing clinician to find the right balance between effectiveness and minimal risk of side effects.

It can take a little time for you to find the best solution, but with some patience and guidance from your doctor, you should be able to access a medication that helps to treat your erectile dysfunction.

MUSE 1000mcg urethral stick

MUSE alprostadil 1000mcg dosages are the highest available for the treatment and are generally only prescribed when the more standard 500mcg dose has not given you the effects you need to achieve and maintain an erection.

It’s possible if you’ve taken MUSE before and found the highest dose best for you that it will be prescribed at the start of treatment, but you’ll need to explain your history of erectile dysfunction and its relevant treatments during your consultation.

MUSE 500mcg urethral stick

MUSE 500mcg is typically the starting dosage to treat erectile dysfunction. Most men will not have any issues with the medication, but should you experience any side effects that concern you, speak with your prescribing clinician, who will be able to offer one of the lower dosage products.

If you’re not finding MUSE is effective at this strength, then a higher dosage or alternative treatment might be offered.

MUSE 125mcg & 250 mcg urethral stick

Although it happens rarely, if you are struggling to tolerate MUSE at 500mcg, then 125mcg and 250mcg dosages are available. Generally speaking, if the medication is effective at the lower dose then that’s the best outcome as it minimises the risks of side effects occurring.

If you’re concerned about tolerating erectile dysfunction treatments then speak with your prescribing clinician, who will be able to offer the lower dose MUSE products.

If you’re still experiencing side effects from MUSE despite the decrease in dosage strength, then a different erectile dysfunction treatment might be recommended.

When should I change dose if I’m using alprostadil?

The most common reasons for adjusting your dosage of any alprostadil medication are because you’re having issues tolerating it or that it isn’t effective enough. If there’s a lower dosage available, then this is usually a viable option to switch to. It is, however, also possible that you’ll need the dosage altered if medication isn’t effective enough and you haven’t had any significant side effects that would prohibit the dose increasing.

Adjusting the dosage of any medication should be done with the advice and monitoring of a doctor. Do not experiment with your ED treatment without first discussing your options.

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This page was medically reviewed by Dr Daniel Atkinson, GP Clinical Lead on August 02, 2022. Next review due on August 01, 2024.

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